Metering electric energy.



No. 671,273. Patented Apr. 2, l90l.

w. c. FISH. METERING ELECTRIC ENERGY.

(Application filed Jan. 26, 1901.)

(No Model.)

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tlnrrnn WALTER C. FISH, OF LYNN, MASSACHUSETTS, ASSIGNOR TO THE GENERALELECTRIC COMPANY, OF NEW' YORK.

METERING ELECTRIC ENERGY.

SPECIFICATION forming part of Letters Patent No. 671,273, dated April 2,1901.

Original application filed-January 18, 1899, Serial No. 702.506. Dividedand this application filed January 26, 1901. Serial No. 44,777. (Nomodel.)

To (tZZ whom, it may concern:

Be it known that I, WALTER C. FISH, a citizen of the United States,residing at Lynn, in the county of Essex, State of Massachusetts,

have invented certain new and useful Improvements in Metering ElectricEnergy, (Case No. 2,040,) of which the following is a specification.

Until very recently it has been the custom to IO charge consumers ofelectrical current or energy supplied from central stations a certainspecified price, depending upon the amount of current or energy used byeach particular consumer. Each consumer has been supplied I usually witha recording-wattmeter acting to integrate the product of current byelectromotive force from instant to instant, and the charges wereproportional to the readings of this instrument. Later, however, itbegan to be realized that this system of charging was unfairboth to theconsumer and to the station. The cost of supplying electrical energy toa particular consumer depends not only on the amount of energy which heactually does take during a given month, but also on the maximum demandwhich he makes upon the station. To speak more accurately, the cost ofsupplying energy from a station is the sum of two quantitiesfirst, thecost of being 0 ready to supply a certain maximum load, and, second, thecost of actually supplying a certain definite load for a certaindefinite time. The first item contains such matters as, for example, theinterest on the cost of 5 the generators, engines, &c., and the salariesof the general office'rs, engineers, superintendents, &c., while thesecond item takes account of the increased amount of coal, oil, &c.,used when a large load is carried for a definite time. It has thereforebeen proposed to place in circuit with each wattmeter amaximum-recording meter, which shall indicate the maximum demand made bythe consumer upon the station during a specified 5 time and'to chargethe consumer a certain amount for the maximum demand which he makes anda certain additional amount for the energy which he actually uses. Thissystem is exceedingly just and satisfactory in all cases Where themaximum demand is sure to occur during the heavy-load hours; butevidently it is possible that a certain consumer may take his maximumload for a given month during the daytime, and it is unfair that in sucha case he should be charged heavily, since during the day the station isusually capable of supplying a load far in excess of that which itactually carries, and,

in fact, is usually glad to sell current ata reduced rate. Anothersolution of the difii- 6o culty has been to install meters which wereadjusted to read at one rate during the fullload hours and at anotherrate during the low-load hours. This is satisfactory in certain specialcases, but is sometimes objectionable, since it fails to take account ofthe fact that a consumer may use lights for only a very few hours eachmonth, and thus pay only a very small hill, though his load when it doescome is such as to cause great diffi- 7o culty and annoyance to thestation. An example of such a consumer would be a theater in a countrytown, which might be open only once a Week, but which, nevertheless,would take a heavy load when the station was least able to furnish it,without running up a bill in any way large enough to compensate for thisobjection.

My present invention contemplates overcoming the difficulties abovementioned by integrating the load at diiiferent rates during difierentparts of the diurnal period corresponding to marked changes of theload-curve of the supply-station and recording the maximum load of theconsumer during the periods corresponding to a definite rate.

The invention involves, besides the novel mode of measuring energyconsumed just set forth, a new system for carrying it out.

The present application is restricted to the 0 improved method ofoperation, the system be ing claimed in a separate application, SerialNo. 702,506, filed January 18, 1899, of which the present application isa division. v

The accompanying drawing represents a.95 system of distribution arrangedin accordance with one form which my present invention may take.

A is a source of electric currentas, for example, a generator at acentral stationfrom which extend lines B 0. Branch circuits leading toindividual-consumption-eir-- ance R is placed in series with thearmature,

and an additional resistance S, capable of being cut out by a switch G,is inserted in series with the resistance R. In series with the main D,I also insert a maximum-meter H. This instrument is indicated here onlyconventionally as consisting of an arm a, carrying a pencil 1;, movingover a scale a. A solenoid d attracts the core e and pulls the arm adownward against the action of an adjustable spring f. Evidently thepencil b will trace a line, as-indicated at g, upon the scale 0, whoselength will indicate the maximum load taken by the consumer since thescale Was renewed. Any other suitable recording instrument may be usedin place of the one shown. The maximum instrument is shunted by a switchK in such a way that when the switch is closed the instrument will ceaseto operate.

It is obvious that by suitably manipulating the switches G and K themethod above outlined may be carried out. As an illustration of onemanner in which this may be accom plished, I have shown an additionalwire M, extending through the system, with branches N N at theparticular consumption-circuits. Each of these branches leads through asolenoid O, which solenoid actuates an insulated rod P against theaction of a spring Q. In the central station I arrange a switch T, whichis capable of supplying current to the wire M, preferably through aresistance U.

The operation of the system thus described is as follows: During thehours of heavy loadfor example, from five oclock p. in. untilmidnightthe switch T is closed. 'Ourrent thus flows from the main Bthrough the resistance U, switch T, and wire M to the wire N, and thencethrough the solenoid O to the wire E and back to the station.. The

solenoid thus energized closes the switch G and opens the switch K. Theresult is to cut out the resistance S in series with the resistance R inthe armature-circuit of the recording-meter and to open the shunt aroundthe maximum-meter. The two-rate meter now runs on the high rate and themaximum-meter becomes operative. Under such conditions the customer willnaturally use as little current as possible and will avoid taking aheavy load for even a short time. As the load goes off from the stat-ionthe switch T will be thrown to the position shown in the drawing. Thiswill open-circuit the coil 0, and the spring Q will close the switch Kand open the switch G. The recording-meter F will now run on the lowrate and the maximum-meter will be inoperative. This will encouragecustomers to use current freely at the time when the station is bestable to furnish it.

It will be obvious that my invention is not restricted to the particulartwo-rate meter apparatus shown nor to the particular method of controlshown, as I may use, for example, any of the arrangements now well knownin the art devised by Kapp, Barstow, and Oxley.

What I claim as new, and desire to secure by Letters Patent of theUnited States, is

1. The method of measuring current or energy taken by a consumer from asystem of electrical distribution, or central stat-ion, which consistsin integrating the load at two different rates during diiferent hours ofthe day, and recording the maximum load during the period of high rateonly.

2. The method of measuring current or energy taken by a consumer from asystem of electrical distribution or central station, which consists inintegrating the load at two different rates during difierent hours ofthe day, and recording the maximum load during a part only of each day.

3. The method of checking the demand of a consumer of electrical energy,which consists in recording the maximum load taken during a part only ofeach day, and in intograting the load during the whole day.

In witness whereof I have hereunto set my hand this 22d day of January,1901.

WALTER O. FISH.

Witnesses:

DUGALD MoK. McKILLoP, JOHN J. WALKER.

